Subcutaneous (SC) and intramuscular (IM) injections

Equipment
SC Method
IM method
Hints

• Syringe
• Needle (27 gauge [orange] or smaller for SC injection; 21–23 gauge [green or blue] for IM injection)
• Medication to be injected. Read the instructions to ensure the delivery route is permissible
• 21-gauge needle for drawing up
• Alcohol swab
• Gauze or cotton
• Hazardous material container
• Gloves

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• Explain to the patient what you are about to do.
• Put on gloves and draw up the medication to be given using the 21-gauge (green) needle. Expel air from the syringe and attach the 27-gauge (orange) needle.
• Swab the skin into a fold in a suitable site (e.g., forearm, triceps area, abdomen). Pinch the skin gently into a fold.
• Insert the needle horizontally into the fold of skin (Fig. 6).
• Draw back on the needle to ensure that you are not in a vein.
• Slowly inject the medication. Withdraw the needle and wipe the area with cotton.

Fig. 6 Subcutaneous injection. Pinch a fold of skin between the thumb and forefinger, then inject into the fold.

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• Explain to the patient what you are about to do.
• Put on gloves and draw up the medication to be given using the 21-gauge (green) needle. Expel air from the syringe and if necessary attach a 23-gauge needle.
• Swab the area to be injected (e.g., upper outer quadrant of buttock [Fig. 7], deltoid area, lateral thigh).
• Insert the needle to full depth perpendicular to the skin.
• Draw back on the syringe to ensure that it is not in a vein.
• Slowly inject the medication. If the patient complains of discomfort, stop for a few seconds until the pain eases, then continue more slowly.
• Withdraw the needle and wipe the area with cotton.

Fig. 7 One of the sites for intramuscular injection.

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In obese individuals, a 21-gauge needle will be needed, especially if injecting the buttock, in order to get as deep as the muscle layer. Injection into subcutaneous fat leads to poor absorption and occasionally to inflammation of the fat.

At some time, you will be asked to perform IM injection in a confused, disturbed individual – often with the aim of sedation. This is permissible under common law, as long as you satisfy yourself that the patient is incapable of informed consent and that your actions are in the best interests of the patient. Think carefully before administering IM sedation to a confused patient who is wandering at night – ask yourself if you have been asked to do it because the nursing staff want a quiet night shift!

If you do administer sedation to a disturbed patient, ensure that you put your own safety first. A flailing arm plus a contaminated needle is a recipe for a needle-stick injury and possible blood-borne infection. Get someone to help you, perhaps by gently restraining flailing arms or by talking to distract the patient.

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